The present invention relates to a method and equipment for detecting whether or not a tool of a machine tool is broken from the quantity of collected chips or particles.
In this specification the term "machining tools" is used to refer to various types and kinds of tools used in machine tools such as cutting tools, milling tools, drilling tools and so on.
There have been devised and demonstrated various methods for detecting tool failures. According to one prior art method, the current flowing to a motor for spinning a tool is detected and when an armature current drops a predetermined level; that is, the level of current at which a normal machining operation is carried out, a tool is detected as being broken. However, in the case of machining of soft works such as epoxy resins, bakelite, woods or soft metals, the difference in torque of the motor between a machining step and a non-machining or nonloaded period is very small so that the correct detection of a tool is very difficult.